The Theory Of Plate Tectonics

II: Plate tectonics shows the features and movement of the Earth. The theory of plate tectonics says that the outer shell of the earth is broken down into pieces often called plates (Korenaga). These plates hover over the mantle creating movement (Marshak). With plate tectonics you can determine the earth’s features without actually seeing it.

Volcanic and Seismic events are major pieces of evidence towards proving that plate tectonics theory is valid (40 marks)

The theory of plate tectonics was first developed by Alfred Wegener. He concluded that the continents seem to have a similar shape and could potentially fit together. This suggested that they were at one time joined together as part of 2 super continents called Gondwanaland and Laurasia was in the north. This theory was said to be proven by the discovery of fossilised remains of a mesosaurus that were found on the coasts of Brazil and Gabon. Sea floor spreading is another theory that supports the idea of plate tectonics; this theory discovered that rock is being formed under the ocean as a new sea floor. Sea floor spreading was shown in the Atlantic, where it is believed the Eurasian and North American plates are moving apart on a

Plate Tectonics is a scientific theory which study how the Earth’s plates are driven and shaped by geological forces to keep them in constant movement. The theory explains the present-day tectonic behavior of the Earth, particularly the global distribution of mountain building, earthquake activity, and volcanism in a series of linear belt. (Pitman, W.C., 2007)

The earth’s surface is made up of many separate pieces called tectonic plates. These tectonic plates are in constant movement. This

The theory of the continental drift is that the continents have slowly drifted to their current location. Alfred Wegener believed that all the seven continents were once a supercontinent known as Pangea. A discovery that came from climate clues like glacial deposits in South America, Africa, Australia and India. Rock and fossils matching evidence found in South America and Africa.

To support the theory of continental drift is through topography, surveying the floors of oceans, charts of rock magnetism, and statistics on rock ages (Trefil & Hazen, 2010). At one time scientist believed that the deep ocean floors were flat; accumulating the sediment that progressively wore away from the prehistoric landmasses (Trefil & Hazen, 2010). However, they discovered steep-walled valleys and elevated highlands. This was evidences that just as the continents are transformed and are active, so to is the seafloor (Trefil & Hazen, 2010). The Mid- Atlantic Ridge, positioned in the central part of the Atlantic Ocean, is recorded to be the longest mountain range on this planet. Volcanoes, lava flow, and earthquakes are a source of

James Hutton was the first scientist to address the Earth was millions of years old, as well as alive and is continuously being formed. Charles Lyell popularized uniformitarianism, and believed the Earth was being shaped by slow moving forces. Alfred Wegener introduced the foundation for the theory of continental drift. Wegener was one of the first to recognize and have an understanding of how the Earth works which required data and information from earth sciences. In the 1960s, the theory for the continental drift became known as the theory of plate tectonics or plate building.

Approximately, the world oceans were 100 to 200 meters (330 to 660 feet) higher in the Early Cretaceous period and 200 to 250 meters (330 to 660 feet) higher in the Late Cretaceous than the sea level of today. This major influence to the physical landscape resulted from increased volcanism due to the final breakup of Pangaea. The increase of global mid-ocean ridge volcanism helped to raise global sea levels by melting polar ice. This caused marine waters to inundate the continents, creating relatively shallow inland seas in North America, South America, Europe, Russia, Africa, and Australia. The surface area of the continents was greatly reduced. During the marine highstand – a time during which sea levels are at their highest – land covered only roughly 18 percent of the Earth’s surface, compared with 2 percent today. This occurrence in the Cretaceous period resulted in extensive formation of chalk and other marine limestone, a type of rock created under warm, shallow marine conditions. Due to the system’s thickness and relatively recent occurrence, Cretaceous rocks croup out in several locations around the

Continental drift was a theory offered by Alfred Wegener in 1912 that hypothesized that all the continents at one time fit together as one land mass. Wegener, explained that the ends of each continent could fit together like a puzzle and that over time the continents drifted apart. "The model explained why the same types of fossils occur in sedimentary rock on both sides of the vast Atlantic Ocean" (Star, 2008, pg. 250), in other words allopatric speciation. Wegener's theory did not have a supporting geological mechanism. Many years later and advances in technology brought about the plate tectonics theory. Essentially it says:

Evaluate how Plate Tectonic Theory helps our Understanding of the Distribution of Seismic and Volcanic Events (40 marks)

The earth is a massive sphere composed of different layers. The layers above the surface are gas, the surface is liquid and solid, but deep below it’s a dense liquid that moves around. The liquids inside the earth move because as the center is heated the material in it is hot and so its density is reduced. Materials with a lower density tend to rise up as materials with higher densities lower, this causes all the materials inside of the earth to

After reading the article, “Continents Adrift”, we learn that our planet is constantly changing, and that this change has to do with continental drift. As noted on page 196, “About 250 million years ago, most of the land on Earth was clumped together. Instead of the seven continents, there was a single large landmass called Pangaea. Over time, Pangaea split apart.” The idea that the continents are drifting or moving apart has been studied by scientists since the late 1700s. For instance, scientists such as Georges-Louis Leclerc Buffon and Alfred Wegener theorized that continents were drifting apart. Although these scientists had the right idea, people did not believe them because their proof wasn’t strong enough. As more scientists

Alfred Wegener claimed that the continents were very slowly drifting apart. The evidence that best supports Wegener’s claim is fossils found in a continent has the same fossil or fossils in the other nearest continent because a fossil can’t fly or swim across the ocean to get to another continent and bury itself. Another example of strong evidence for Continental drift is there are scratch marks from rocks scratching together in Africa and South America that line up exactly because this is a very extraordinary piece of evidence and why can scratches from Africa and South America line up exactly unless Continental Drift is true. The final piece of convincing evidence is the fit of continents, the fit of continents make the continents look like

In the middle of the eighteenth century, James Hutton proposed a theory, uniformitarianism; “the present is the key to the past”. It held that processes such as geologic forces- gradual and catastrophic-occurring in the present were the same that operated in the past. (Matt Rosenberg, 2004) This theory coincides with the theory of Continental Drift that was first proposed by Abraham Ortelius in December 1596, who suggested that North, South America, Africa and Eurasia were once connected but had been torn apart by earthquakes and floods. He also discovered that the coasts of the eastern part of South America and the